Process for interrupting connections in vacuum valves



I Aug. 29, 1933. B WIENECKE PROCESS. FOR INTERRUPTING CONNECTIONS IN VACUUM VALVES Filed Oct. 24, 1928 2 Sheets-Sheet 1 2/82? for.-

Aug. 29, 1933. B, WIENECKE 1,924,256

PROCESS FOR INTERRUPTING CONNECTIONS IN VACUUM VALVES Filed Oct. 24, 1928 2 Sheets-Sheet 2 fin? Zim electric currents and heat.

PROCESS FOR. 'INTERRUPTING CONNEC- TIQNS IN VACUUM VALVES Bruno Wienecke, Berlin, Germany Application October 24, 1928, SerialNo. 314,671,

1 and in Germany October 29, 1927 Claims. (01. 250427.25)

My invention relates to a method of severing connections in thermionic valves and. the like and to an arrangement for carrying out such a method.

In operating with thermionic valves, andmore particularly in manufacturing such valves, it is often necessary after the completion of the valves to sever certain conductive connections present within the envelopes of the valves. The invention relates to a method of effecting such severing. The problem which' forms the basis for the invention may be solvedfby making. the connection with a thin wire which is caused to melt by means of a current passed through it for the purpose. The leads through the glass wall of the valve that are necessary, however, do not generally exist from the outset. If special leads are provided which are required merely once for the purpose of such melting and otherwise are not used, such leads are subsequently during the whole life of the valve a source of interference in electrical respects or may cause confusion.

According to my invention the lead to be severed is given the form of a thin metal tape which at suitable places is provided with one or several sufliciently large holes, the cross section at the places in question thus becoming very 'small. Such portions of reducedcross-section may by means of an alternating electro-magnetic field, produced in the neighbourhood of the valve, be caused to evaporate or disperse.

In this connection the metal tape to be severed is provided of such dimensions and the disposition of the alternating current field is such that in the metal tape eddy currentsare generated of such intensity that at the place of the severing the evaporation and/or dispersal temperature is reached. I

The necessity of severing conductive connections may occur in various respects. During the process of evacuation it may, for instance, be desirable for certain metal parts to be conductively connected with one another which in the finished valve need no longer be connected or even must not be connected.

It is, for instance, frequently desirable for ob taining a good vacuum that all metal elements inside the envelope should be brought during the process of evacuation, to an increased temperature. For increasing the temperature of such conductor elements it may be desirable to connect some of the conductor parts in such a manner as to secure good conductivity both for This is explained particularly by reference to an example of construction and in, connection with a multiple valve represented in the accompanying drawings, by way of example.

Fig. 1 shows the valve infront view theglass bulb being partly broken away. a M

Fig. 2 shows ina'side view the'upper portion of the valve represented in Fig. l.

Fig. 3" shows in perspective the connecting bridge according' tothe invention on a larger scale. a

Fig. 4 shows the parts 4, 5 and 6 in section taken on a -horizontal plane. i f v Fig. 5 is a development of Fig. 1, showing more clearly the connection between the singular electrodes. V In the figure 1 means the glass bulb containing the two electrode systems2 and 3, the third electrode system 4 and the coupling elements, each united to groups 5 and 6.

The construction of the electrode System52, 3 and 4 is to be seen in detail inFig. "5, The electrode system 2 consists of the anode '7, the grid 16, the cathode 17. In a similar way the electrode system 3 consists of the anode 8, the grid 18, the cathode 19, whilst the electrode system 4 possesses the anode 20, the grid 21 and the cathode 22. v The anodes 7 and 8 of systems 2 and 3 are connected by a bridge 9preferably of magnesium, for instance a piece of magnesium foilin such a manner that anode 'I is in conductive connection with holder 10, anode 8 with holder 11, whilst between the holders 10 and 11 the bridge 9 is arranged. This bridge shows a UNITED "STATES PATENT UOFFICEY' circular hole 12 whichmay be easily produced valve the connection is to be severed, a coil carrying alternating current is placed round the valve. currents, for a short period, the bridge9 is severed at the points 13 and 14. As compared After continuance of the high frequency with other possibilities of severing the dispersal persal of the magnesium no metallic precipita- 7 the anode resistance 23 connected by the leading means of wire 41 with the grid-leak 42.

free end of the latter is provided with a wire 43' wire 24 with the anode '7 of the electrodesystem 2, by means of leading wire 25 with the bridge 9, by means of wire 26 with the grid condenser 27, whilst at the other end of the anode resistance 23 a leading wire 28 is provided for the outset. The other electrode of the grid condenser 27 is connected by means of Wire 29 with the grid 18 of electrode system 3 and by means of wire 30 with the grid-leak 31. The free end of the latter is provided with a wire 32 for the outset. The input circuit is connected with the wire 32 and a wire 33 leading to the input grid 16.

The group 6 of the coupling elements contains the anode resistance 34 connected by the leading wire 35 with the anode 8 of the electrode system 3, by means of the leading wire 36 with the bridge 9, by means of wire 37 with the grid condenser 38, whilst at the other end of the anode resistance 34 a leading wire 39 is provided for the outset. The other electrode of the grid condenser 38 isiconnected by means of wire 40 with the grid 21 of electrode system 4 and by The for the outset. The output circuit is connected withthe anode 20 by means of wire 44.

The heating circuit for the cathodes 17 and19 consists of the leading'wire 45, the cathode 17, the connecting wire 46, the cathode 19 and the leading wire 47. Therefore, the cathodes 17 and 19 are connected in series. To the heating filament 22 the heating current is led by means I of wires 48 and 49.

My invention is not limited to the severing of conductive connections. In certain circumstances it may be useful to remove non-conductors existing within a vacuum vessel. This may also be effected by the invention-for instance by the non-conductor in question being first secured by metallic holders, such as magnesium bridges from which it is subsequently freed by eddy current evaporation.

I claim:

1. In an evacuated vessel, metallic electrodes, a metallic sheet connecting 'said electrodes, said metallic sheet having a hole in its middle part for being severed by eddy currents induced in said metallic sheet from outside.

2. In an evacuated vessel, metallic electrodes, a thin sheet of magnesium connecting said electrodes, said sheet of magnesium having a hole in its middle part for being severedby eddy currents induced in said magnesium sheet from outside.

3. In an evacuated vessel, metallic electrodes, a thin sheet of magnesium connecting said elec'- trodes, said thin sheet of magnesium having a circular hole thecentre of which coincides, as far as possible, with the point of intersection of the diagonals of the surface of said sheet, in orderthat said sheet may be severed by eddy currents induced from outside.

'4. A thermionic valve comprising several systems of electrodes, a thin sheet of magnesium connecting corresponding electrodes of different systems, said magnesium sheet having a hole in order to form a quite narrow portion in the sheet of magnesium.-

5. A thermionic valve comprising several systems of electrodes, a thin sheet of magnesium connecting the anodes of different systems, said magnesium sheet having a hole in order to form a quite narrow portion in the sheet of mag nesium.

BRUNO WIENECKE. 

